GASP XXXIX: MeerKAT hunts Jellyfish in A2626

TL;DR

This study uses MeerKAT HI observations to confirm two jellyfish galaxies in A2626, revealing their HI stripping, high velocities, and multi-phase gas tails, highlighting ram pressure stripping and HI-to-H2 conversion as key depletion processes.

Contribution

First detailed HI study of jellyfish galaxies in A2626, confirming two as JFGs and analyzing their gas stripping and phase conversion processes.

Findings

Two galaxies confirmed as jellyfish galaxies with low HI content.

HI, Halpha, and CO tails extend about 50 kpc, showing multi-phase gas stripping.

HI-to-H2 conversion and ram pressure stripping are major gas depletion mechanisms.

Abstract

We present MeerKAT HI observations of six jellyfish candidate galaxies (JFCGs) in the galaxy cluster, A2626. Two of the six galaxies JW100 and JW103, that were identified as JFCGs from B-band images, are confirmed as jellyfish galaxies (JFGs). Both of the JFGs have low HI content, reside in the cluster core, and move at very high velocities ($\sim$ 3$\sigma_{cl}$). The other JFCGs, identified as non-jellyfish galaxies, are HI rich, with HI morphologies revealing warps, asymmetries, and possible tidal interactions. Both the A2626 JFGs and three other confirmed JFGs from the GASP sample show that these galaxies are HI stripped but not yet quenched. We detect HI, Halpha, and CO tails of similar extent ($\sim$ 50 kpc) in JW100. Comparing the multi-phase velocity channels, we do not detect any HI or CO emission in the northern section of the tail where Halpha emission is present, possibly due to prolonged interaction between the stripped gas and the ICM. We also observe an anti-correlation between HI and CO, which hints at an efficient conversion of HI to H2 in the southern part of the tail. We find that both RPS and HI-to-H2 conversion are significant depletion channels for atomic gas. HI-to-H2 conversion is more efficient in the disc than in the tail.